A Parts-Per-Billion Measurement of the Antiproton Magnetic Moment

The Big Bang theory hypothesizes that the universe originated in a super-dense hot state. However, researchers have long known that one problem (of many) with that theory is that, in the lab, matter and antimatter come into existence in exactly equal amounts. So if the universe had ever been extremely dense and hot, matter and antimatter would have annihilated each other with almost nothing left over. To solve this problem, researchers have long searched for the tiniest hint that matter and antimatter are not perfectly symmetrical and therefore would not have exactly cancelled each other in Big Bang. But the latest extremely sensitive measurements reported in Nature have further confirmed that no such asymmetry exists.

If, contrary to the Big Bang theory, the universe has always had low density, then matter and antimatter could have become separated from each other without mass annihilation. Nobel Laureate Hannes Alfven and colleagues worked out the way that the action of electrical, magnetic and gravitational forces in any dilute plasma would separate matter and antimatter at very large scales.